The present invention relates generally to computer-assisted design of vehicles and, more specifically, to a system and method for design of experiments using direct surface manipulation of a mesh model in the computer-assisted design of a vehicle.
Vehicle design, and in particular the design of an automotive vehicle, has advanced to a state in which computer-assisted design techniques are frequently incorporated in the development of a new vehicle or redesign of an existing vehicle. Enhanced visualization software tools allow for interactive display and manipulation of large geometric models, including models developed using computer aided design (CAD). In the field of vehicle design, the use of computer aided design and visualization techniques are especially beneficial in designing, packaging, and assembling the various systems incorporated within the vehicle to maximize the design and functional capabilities of these vehicles. Advantageously, potential vehicle system designs can be considered in a timely and cost-effective manner by analyzing a digital representation of a proposed design versus preparing an actual vehicle model.
One aspect of the design process is to construct a geometric model of the proposed design using a technique known as computer-aided design (CAD). Another aspect of the design process is the use of mathematical tools referred to as computer-aided engineering (CAE) to constrain and guide the designer in evaluating the design. The use of CAE allows for verification of design intent and a prediction of a mechanical behavior of the design, including its systems, subsystems, and components. Examples of CAE techniques include finite element analysis (FEA) and computational fluid dynamics (CFD). Advantageously, the increased computing power of modern computers has reduced the amount of time required to perform a CAE simulation. Therefore, CAE tools can be utilized earlier in the product development process and applied to a wide range of product development activities.
One product development activity that has benefited from enhanced CAE computational capabilities is Design of Experiments (DOE). DOE is an engineering design practice that enables a designer to conduct a series of tests corresponding to variations in a set of predetermined design parameters. One benefit of a DOE simulation is that a test in the past would require a physical experiment on a physical prototype, which can now be performed using a CAE simulation and a mathematical or computer representation of a geometric model. As such, the DOE can be conducted in an early phase of the product development process and proposed modifications to the design can be expeditiously analyzed.
With respect to the design of the exterior shape of a vehicle, an airflow DOE provides aerodynamic information regarding the exterior shape of the vehicle. CFD is used to calculate aerodynamic properties, ranging from drag and lift coefficients to wind-noise characteristics, in response to a set of vehicle exterior shape parameters. Since the CFD simulation uses a mathematical representation of the geometric model of the vehicle, the airflow DOE can be performed early in the design process before a physical prototype is built.
Currently, the DOE process includes the steps of importing a CAD model of a particular design such as the exterior shape of the vehicle. The CAD model is converted into a mesh model and the CFD analysis is performed on the mesh model to generate a response of the CAD system. Based on the response obtained in the CFD analysis, the predetermined DOE parameters can be modified. The CAD model is updated in light of the modified DOE parameters. However, modifying the CAD model in a CAD system is a more time-consuming task that has to be performed each time a change is made to the DOE parameter set. Also, using a CAD system to update the mesh model is a time consuming and costly process. Thus, there is a need in the art for a system and method of direct modification of a mesh model based on DOE parameters using direct surface modeling to eliminate the need to update the CAD model each time a DOE parameter is modified.